AMERICAN HYMENOPTERA. 119 



DESCRIPTIONS OF NEW A1VT-EIKE AND MYRME- 

 COPHILOUS HYMENOPTERA. 



BY CHARLES THOMAS BRUES. 



Laboratory of the U. S. Fish Commission, Woods Hole, Mass Sept. 6, 1902. 



The present descriptions and notes are based upon Hymenoptera 

 collected while searching for ants and myrniecophiles. As many 

 insects not associated with ants are found at such times, only those 

 are included which are evidently myrmecophilous or which re- 

 semble ants in form and habitus. All of the ten new species belong 

 either to the Proctotrypoidea or Ichneumonidse, two groups rich in 

 myrmecophilous and ant like species. 



NORTH AMERICAN SPECIES OF PEZOMACHUS. 



Females. 



Head black or piceous 2. 



Head rufous or yellowish. . . 12. 



2. Thorax at least in part black or piceous 3. 



Thorax wholly reddish 10. 



3. Thorax uniformly piceous brown or black. . • ; 4. 



Thorax bicolored 8. 



4. Abdominal petiole wholly black 5. 



Abdominal petiole, with pale band at apex 7. 



Abdominal petiole brown, antennae stout 4. call foriiiciiM Ashm. 



5 Legs, including coxse, wholly reddish or yellowish 6. 



Legs, or at least coxse and femora black ; antennae 18-jointed. 



1. nigrellus Ashm. 



6. Anterior lobe of thorax longer than the posterior one ; antennae 19-jointed. 



2. obesus Ashm. 

 Posterior lobe longer than anterior alaskensis Ashm. 



7. Lateral tubercles of abdominal petiole not prominent; ovipositor as long as 



the petiole ; antennae 21-jointed 5. pettitii Cress. 



Lateral tubercle very prominent; ovipositor as long as first two abdominal 

 segments; antennas 22 -jointed (5. anguli) ris sp. nov. 



8. Thorax with anterior node ferruginous, posterior one more or less black. . 9. 

 Thorax black, with ferruginous antenna? 19-jointed. 



8. macul icoll i*. sp. nov. 



9. First abdominal segment with prominent tubercles and scarcely dilated behind 



them ; antennae 23-jointed 9. geiltilis Cress. 



First abdominal segments broad with inconspicuous tubercles, and much di- 

 lated behind them ; antennas 20-jointed 10. wheelcri sp. nov. 



10. First segment only of abdomen pale 7. I an till us Cress. 



First two of abdominal segments at least in part pale 11. 



TRANS. AM. ENT. SOC, XXIX. (15* J MARCH. 1903. 



